1. Field of the Invention
The present invention relates to a bicycle on which a person can efficiently ride in a comfortable posture along a slope and effectively utilize the strength of the legs while pedaling along a level road.
2. Description of the Background Art
In general, when going up a slope on a bicycle, as shown in FIG. 9, a rider along with the bicycle inclines backward with its uphill gradient. This forces the rider to pedal while bending the upper body more forward than when riding along a level road. This posture hinders the rider from exerting the strength of the legs effectively. Or, the rider may come apart from the saddle, thus forcing the rider to use significantly more labor.
In order to reduce labor taken to ride along an uphill, therefore, a bicycle in which the position of a saddle can be adjusted has conventionally been developed. However, any such bicycle is difficult to operate and handle (refer to Registered Utility Model Publication No. 36881, Japanese Patent Laid-Open Publication No. 57-114773 and Japanese Patent Laid-Open Publication No. 8-282562).
In addition, a chainless bicycle has also been developed in which the shaft of the rear wheel can be directly rotated using crank-attached pedals. This helps lighten the bicycle and simplify its structure. In such a bicycle, however, its body may turn over backward around a rear wheel on an uphill slope.
The above described conventional bicycle in which the position of the saddle can be adjusted has the problem of making it harder for the rider to operate and handle it. On the other hand, the chainless bicycle in which the shaft of the rear wheel can be directly rotated using crank-attached pedals has the problem of turning its body back around the rear wheel on an uphill slope.